scsi: ufs: Use data structure size in pointer arithmetic

Use the structure size in pointer arithmetic instead of an opaque 32
bytes for the over-allocation of descriptors.
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs.h

@@ -40,7 +40,7 @@
 #include <linux/types.h>
 #include <uapi/scsi/scsi_bsg_ufs.h>
 
-#define GENERAL_UPIU_REQUEST_SIZE 32
+#define GENERAL_UPIU_REQUEST_SIZE (sizeof(struct utp_upiu_req))
 #define QUERY_DESC_MAX_SIZE       255
 #define QUERY_DESC_MIN_SIZE       2
 #define QUERY_DESC_HDR_SIZE       2

drivers/scsi/ufs/ufshcd.c

@@ -2262,7 +2262,6 @@ static void ufshcd_prepare_utp_query_req_upiu(struct ufs_hba *hba,
 	struct utp_upiu_req *ucd_req_ptr = lrbp->ucd_req_ptr;
 	struct ufs_query *query = &hba->dev_cmd.query;
 	u16 len = be16_to_cpu(query->request.upiu_req.length);
-	u8 *descp = (u8 *)lrbp->ucd_req_ptr + GENERAL_UPIU_REQUEST_SIZE;
 
 	/* Query request header */
 	ucd_req_ptr->header.dword_0 = UPIU_HEADER_DWORD(
@@ -2284,7 +2283,7 @@ static void ufshcd_prepare_utp_query_req_upiu(struct ufs_hba *hba,
 
 	/* Copy the Descriptor */
 	if (query->request.upiu_req.opcode == UPIU_QUERY_OPCODE_WRITE_DESC)
-		memcpy(descp, query->descriptor, len);
+		memcpy(ucd_req_ptr + 1, query->descriptor, len);
 
 	memset(lrbp->ucd_rsp_ptr, 0, sizeof(struct utp_upiu_rsp));
 }